Automatic speech recognition (ASR) systems are used to facilitate a number of functions at a vehicle. Rather than providing text input via physical devices, vehicle occupants can speak commands that are received at a microphone and ultimately converted to text. The speech-to-text output can then be read to determine what information or command the vehicle occupant is communicating.
In order to recognize a wide variety of possible words used to convey information that can involve a range of topics, the ASR system may access grammars of significant size when receiving speech. As the size of grammars increases, so does the time needed to process speech. To reduce the grammar size used by ASR systems, it can be helpful to first identify the context of the received speech. Context-based grammars can be smaller than those needing to recognize a variety of topics. Present systems generally identify speech context by asking a speaker to expressly identify the context via a command that places the ASR system in a condition to receive context-related information. For example, if a speaker wants to navigate to a point-of-interest (POI), the speaker can say “POI, navigate to Belle Isle Park.” A gate command (in this case, “POI”) can alert the ASR system that a POI request will follow. However, a significant number of speakers may not preface their command with an initiating word recognized by the ASR system—or any initiating word. Without the initiating word, the ASR system may—at best—take a significant amount of time to recognize received speech or at worse fail to recognize the speech. It would be helpful to configure the ASR system so that it can recognize POIs or addresses without reliance on an initiating word to alert the system.